Method of Determining Smoke Detector Spacing in High Ceiling Applications

Abstract

Simple tools for the design application of smoke detectors in commercial spaces with high ceilings and/or complex geometries do not exist due to the complexity in accurately estimating smoke densities and smoke detector activation characteristics. The response of commercial smoke detectors to UL/ULC standard flaming acceptance test fires and non-standard test fires in large open spaces with ceiling heights varying from 3 m to 21 m with radial distances from the fires up to 11.4 m is measured. Two algebraic models intended for unconfined ceilings, the two-zone computer model CFAST and the computational fluid dynamics computer model FDS are compared against each other and the experimental results. The ability to predict obscuration levels and detection times for these fires is evaluated. Recommendations are made for using the various models in commercial applications.